TWI830481B - Mold steel with excellent mirror finishing properties - Google Patents
Mold steel with excellent mirror finishing properties Download PDFInfo
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- TWI830481B TWI830481B TW111142154A TW111142154A TWI830481B TW I830481 B TWI830481 B TW I830481B TW 111142154 A TW111142154 A TW 111142154A TW 111142154 A TW111142154 A TW 111142154A TW I830481 B TWI830481 B TW I830481B
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 77
- 239000010959 steel Substances 0.000 title claims abstract description 77
- 239000012535 impurity Substances 0.000 claims description 9
- 229910052760 oxygen Inorganic materials 0.000 claims description 5
- 229910052748 manganese Inorganic materials 0.000 claims description 3
- 229910052750 molybdenum Inorganic materials 0.000 claims description 3
- 229910052717 sulfur Inorganic materials 0.000 claims description 3
- 229910052804 chromium Inorganic materials 0.000 claims description 2
- 229910052720 vanadium Inorganic materials 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims 1
- 229910052755 nonmetal Inorganic materials 0.000 claims 1
- 239000000463 material Substances 0.000 abstract description 16
- 239000004033 plastic Substances 0.000 abstract description 13
- 229920003023 plastic Polymers 0.000 abstract description 13
- 238000000465 moulding Methods 0.000 abstract description 6
- 238000005299 abrasion Methods 0.000 abstract description 2
- 230000002349 favourable effect Effects 0.000 abstract 1
- 239000000203 mixture Substances 0.000 description 21
- 238000005498 polishing Methods 0.000 description 19
- 230000007797 corrosion Effects 0.000 description 16
- 238000005260 corrosion Methods 0.000 description 16
- 239000002893 slag Substances 0.000 description 15
- 238000011156 evaluation Methods 0.000 description 14
- 150000001247 metal acetylides Chemical class 0.000 description 12
- 238000003756 stirring Methods 0.000 description 12
- 238000007670 refining Methods 0.000 description 11
- 238000012360 testing method Methods 0.000 description 11
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 10
- 238000012545 processing Methods 0.000 description 9
- 238000005496 tempering Methods 0.000 description 8
- 239000003082 abrasive agent Substances 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 4
- 238000010137 moulding (plastic) Methods 0.000 description 4
- 238000010791 quenching Methods 0.000 description 4
- 230000000171 quenching effect Effects 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 238000007872 degassing Methods 0.000 description 3
- 229910003460 diamond Inorganic materials 0.000 description 3
- 239000010432 diamond Substances 0.000 description 3
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000001953 sensory effect Effects 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910001566 austenite Inorganic materials 0.000 description 2
- 230000003749 cleanliness Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 238000005204 segregation Methods 0.000 description 2
- 238000010313 vacuum arc remelting Methods 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000002925 chemical effect Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000002310 reflectometry Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
Description
本發明係關於適合用以將超鏡面的塑膠製品予以成形之超鏡面最終加工之鏡面最終加工用模具用鋼。The present invention relates to a mold steel for mirror finish processing that is suitable for use in molding super mirror-surface plastic products.
近年來使用於電子設備或生活用品的容器及透鏡等之塑膠製品，要求表面為鏡面、與高強度等。因此，對於用以將這樣的高鏡面塑膠製品予以成形之模具，要求模具本身的表面的高鏡面性、耐磨耗性優良、及耐蝕性優良等。作為滿足這樣的要求之金屬材料，以往使用SUS420系鋼等馬氏體不鏽鋼。In recent years, plastic products such as containers and lenses used in electronic equipment or daily necessities require mirror surfaces and high strength. Therefore, a mold for molding such a highly mirror-finished plastic product is required to have a high mirror-like surface, excellent abrasion resistance, and excellent corrosion resistance, etc. of the mold itself. As metal materials that meet such requirements, martensitic stainless steels such as SUS420 series steel have been used in the past.
然而，最近，塑膠製品所要求之鏡面性進一步提高，同時，模具表面的最終加工編號逐漸從#8000的高鏡面變為#14000的超鏡面。因此，對於模具用鋼，作為超鏡面的塑膠製品的成形用模具，亦期望進一步提高鏡面最終加工性之模具用鋼的開發。However, recently, the mirror surface required for plastic products has been further improved. At the same time, the final processing number of the mold surface has gradually changed from #8000 high mirror surface to #14000 super mirror surface. Therefore, for mold steels, it is also desired to develop mold steels that further improve the final processability of mirror surfaces as molds for molding plastic products with super mirror surfaces.
專利文獻1中，揭示藉由添加Zr來控制夾雜物組成之塑膠成形模具用鋼。該模具用鋼中，使鋼液中的氧化物浮起，將觀察氧化物的浮起面時全部氧化物中ZrO 2所佔之比例控制在95面積%以上。專利文獻2中，揭示藉由控制碳氮化物的個數密度與大小，來提高鏡面性之高耐蝕性塑膠成形模具用鋼。專利文獻3中，揭示控制碳化物的大小及碳化物間距離，同時將碳化物密集帶的面積為1000μm 2以上者作為材料項目時，控制該材料項目的最大長度與面積率，藉此使鏡面性提升之塑膠模具用鋼。再者，專利文獻4中，揭示以面積百分率計，將非金屬夾雜物的上限設為0.015%之塑膠射出成形用模具材料。專利文獻5中，揭示使含有Mo及W之細微碳化物析出。 [先前專利文獻] [專利文獻] Patent Document 1 discloses steel for plastic molding molds that controls the composition of inclusions by adding Zr. In this steel for molds, the oxides in the molten steel are floated, and the proportion of ZrO 2 in all oxides when observing the floating surface of the oxides is controlled to be above 95 area %. Patent Document 2 discloses a steel for plastic molding molds with high corrosion resistance that improves mirror surface properties by controlling the number density and size of carbonitrides. Patent Document 3 discloses controlling the size of carbides and the distance between carbides, and controlling the maximum length and area ratio of the material item when the area of the carbide dense zone is 1000 μm 2 or more as a material item, thereby making the mirror surface Steel for plastic molds with improved performance. Furthermore, Patent Document 4 discloses a mold material for plastic injection molding in which the upper limit of non-metallic inclusions is set to 0.015% in terms of area percentage. Patent Document 5 discloses the precipitation of fine carbides containing Mo and W. [Prior Patent Document] [Patent Document]
[專利文獻1]日本特開2006-28564號公報 [專利文獻2]日本特開2014-189822號公報 [專利文獻3]日本特開2015-168850號公報 [專利文獻4]日本特開昭64(日本特開平1)-25950號公報 [專利文獻5]日本特開平2-175845號公報 [Patent Document 1] Japanese Patent Application Publication No. 2006-28564 [Patent Document 2] Japanese Patent Application Publication No. 2014-189822 [Patent Document 3] Japanese Patent Application Publication No. 2015-168850 [Patent Document 4] Japanese Patent Application Laid-Open No. 64 (Japanese Patent Application Laid-Open No. 1)-25950 [Patent Document 5] Japanese Patent Application Publication No. 2-175845
[發明所欲解決之課題][Problem to be solved by the invention]
然而，超鏡面的塑膠成型用模具，一般利用鑽石磨料或氧化鋁磨料等進行最終拋光，磨料的直徑越小可得到鏡面性越高的模具表面。由於拋光作業係如#3000→#8000→#14000般每階段性地進行拋光，模具表面最終會變成暴露於利用粒徑小的磨料之長時間的拋光。However, super-mirror plastic molding molds generally use diamond abrasives or alumina abrasives for final polishing. The smaller the diameter of the abrasive, the higher the mirror surface of the mold can be obtained. Since the polishing operation is performed in stages such as #3000→#8000→#14000, the mold surface will eventually be exposed to polishing using abrasives with small particle sizes for a long time.
這樣長時間的拋光，由於模具材料中所含之粗大的碳氮化物及非金屬夾雜物會因拋光粉而被挖出，粗大的碳化物及非金屬夾雜物會在拋光中脫落，剩下的孔洞會變成針孔，失去超鏡面性。這樣的鏡面最終加工性差的模具用鋼，有重新拋光作業及再加工等產生額外成本的問題點。In such long-term polishing, the coarse carbonitrides and non-metallic inclusions contained in the mold material will be dug out by the polishing powder, and the coarse carbides and non-metallic inclusions will fall off during polishing, leaving the remaining The holes will turn into pinholes and lose their supermirror properties. Such steel for molds with poor final processability of the mirror surface has the problem of additional costs such as re-polishing and re-processing.
又，由於針孔亦有磨料的滲入或成為起點而發生生鏽的情況，考量磨料難以滲入模具用鋼的觀點，要求高硬度，且要求難以生鏽的耐蝕性。In addition, since pinholes may also penetrate abrasives or serve as starting points to cause rust, mold steel is required to have high hardness and corrosion resistance that makes it difficult for abrasives to penetrate into mold steels.
因此，以往為了得到難以產生針孔、鏡面最終加工性高的模具用鋼，以使粗大的碳化物及非金屬夾雜物變少的方式，以及以使硬度及耐蝕性變高的方式，對於塑膠成形模具用鋼的製造方法及組成等施加改良。然而，以往的模具，在發揮最近的超鏡面的塑膠成形用模具的需求性能方面有問題。Therefore, in the past, in order to obtain mold steels that are less likely to produce pinholes and have high mirror finish processability, plastics have been processed to reduce coarse carbides and non-metallic inclusions and to increase hardness and corrosion resistance. The manufacturing method and composition of steel for forming molds have been improved. However, conventional molds have problems in achieving the required performance of recent super-mirror plastic molding molds.
專利文獻1中記載的模具用鋼，藉由在組成中添加Zr，來控制夾雜物組成，但有伴隨著Zr的添加而成本變高、Zr的產率不穩定等問題。又，針對鏡面性，#8000的高鏡面的情況下不會產生針孔，但在#14000的超鏡面拋光時，由於鋼材的硬度低至約40HRC，有難以得到超鏡面的問題點。再者，專利文獻1實際上如其實施例所示，由於Cr含量低，亦有耐蝕性低、因長時間的拋光而產生生鏽、以生鏽為起點而產生針孔的問題點。The steel for molds described in Patent Document 1 controls the inclusion composition by adding Zr to the composition. However, there are problems such as the cost increases with the addition of Zr and the yield of Zr is unstable. In addition, regarding mirror properties, pinholes will not occur in the case of a high mirror surface of #8000, but when polishing to a super mirror surface of #14000, there is a problem that it is difficult to obtain a super mirror surface because the hardness of the steel is as low as about 40HRC. Furthermore, as shown in the examples of Patent Document 1, the Cr content is low, so the corrosion resistance is low, rust occurs due to polishing for a long time, and pinholes are generated starting from rust.
專利文獻2及3中記載的模具用鋼，藉由使用SUS420J2系鋼種來確保硬度與耐蝕性，進一步針對碳化物的個數與大小進行限制，藉此提高鏡面性。然而，此等專利文獻2及3完全沒有提及非金屬夾雜物，其模具用鋼中，由於未控制非金屬夾雜物，在超鏡面拋光時，有無法避免非金屬夾雜物所致之針孔的產生的問題。The mold steels described in Patent Documents 2 and 3 use SUS420J2 series steel to ensure hardness and corrosion resistance, and further limit the number and size of carbides to improve mirror finish. However, these patent documents 2 and 3 do not mention non-metallic inclusions at all. In the steel for molds, since non-metallic inclusions are not controlled, pinholes caused by non-metallic inclusions cannot be avoided during super mirror polishing. problems that arise.
專利文獻4及5中記載的模具用鋼，藉由使用SUS420J2系鋼種來確保硬度與耐蝕性，並控制非金屬夾雜物的面積率及氧量。然而，僅控制非金屬夾雜物的面積率，無法解決超鏡面拋光時產生針孔的問題。The mold steels described in Patent Documents 4 and 5 ensure hardness and corrosion resistance by using SUS420J2 steel grade, and control the area ratio and oxygen content of non-metallic inclusions. However, only controlling the area ratio of non-metallic inclusions cannot solve the problem of pinholes generated during supermirror polishing.
本發明係有鑑於該問題所完成者，目的在於提供具有適合用以將超鏡面的塑膠製品予以成形之優良的鏡面性，且耐磨耗性及鏡面最終加工性優良的模具用鋼。 [解決課題之方式] The present invention was accomplished in view of this problem, and aims to provide a mold steel that has excellent mirror properties suitable for molding super-mirror plastic products and has excellent wear resistance and mirror finish processability. [Methods to solve problems]
本發明之鏡面最終加工性優良的模具用鋼，係特徵為： 含有： C：0.20～0.50質量%， Si：0.10～1.50質量%， Mn：0.10～0.70質量%， Cr：10.5～20.0質量%， Ni：1.00質量%以下， Mo：0.05～1.00質量%， V：0.01～1.00質量%； 剩餘部分：具有由Fe及不可避免的雜質構成之組成； 前述不可避免的雜質之中，下述成分被限制在： Al：0.007～0.035質量%， S：0.0020質量%以下， O：0.0015質量%以下， Ca：0.0020質量%以下， Mg：0.0020質量%以下； 鋼材剖面中，等效圓直徑8.0μm以上的非金屬夾雜物的面積率為0.00016%以下； 為等效圓直徑為5.0μm以上的非金屬夾雜物，且含有2質量%以上選自由Al、Mg及Ca構成之群組中之任一成分者，在分別設[Ca]、[Mg]、[Al]為Ca、Mg、Al的含量(質量%)，且設為X=[Ca]/([Mg]+[Al])時，X值未達0.3的夾雜物的個數密度為0.60個/100mm 2以上且未達8.0個/100mm 2，同時X值為0.3以上的夾雜物的個數密度未達3.0個/100mm 2。 The steel for molds with excellent mirror finish processability of the present invention is characterized by containing: C: 0.20 to 0.50 mass%, Si: 0.10 to 1.50 mass%, Mn: 0.10 to 0.70 mass%, Cr: 10.5 to 20.0 mass% , Ni: 1.00 mass% or less, Mo: 0.05 to 1.00 mass%, V: 0.01 to 1.00 mass%; Remainder: composed of Fe and unavoidable impurities; Among the aforementioned unavoidable impurities, the following components Restricted to: Al: 0.007~0.035 mass%, S: 0.0020 mass% or less, O: 0.0015 mass% or less, Ca: 0.0020 mass% or less, Mg: 0.0020 mass% or less; In the steel section, the equivalent circle diameter is 8.0 μm The area ratio of the above non-metallic inclusions is 0.00016% or less; they are non-metallic inclusions with an equivalent circle diameter of 5.0 μm or more, and contain 2 mass % or more of any one selected from the group consisting of Al, Mg and Ca For components, when [Ca], [Mg], and [Al] are respectively the contents (mass %) of Ca, Mg, and Al, and X=[Ca]/([Mg]+[Al]), The number density of inclusions with an
該鏡面最終加工性優良的模具用鋼中，特徵為例如進一步在Mo+1/2W：0.05～1.00質量%的範圍內含有W。 [發明之效果] This mold steel having excellent mirror finish workability is characterized by further containing W in the range of Mo+1/2W: 0.05 to 1.00 mass %, for example. [Effects of the invention]
根據本發明，可得到作為超鏡面的塑膠製品的成形用模具有效的進一步提高鏡面最終加工性之模具用鋼。According to the present invention, it is possible to obtain mold steel that is effective as a mold for molding super mirror-surface plastic products and further improves the final processability of the mirror surface.
以下，針對本發明的實施形態，具體地進行說明。首先，針對本發明之鏡面最終加工性優良的模具用鋼的組成限定理由進行說明。Hereinafter, embodiments of the present invention will be specifically described. First, the reason for limiting the composition of the mold steel having excellent mirror finish workability of the present invention will be explained.
「C：0.20～0.50質量%」 C係形成碳化物，同時是固溶於鋼材的基底使硬度提升之重要的元素。為了得到超鏡面，模具的淬火-回火硬度必須為45HRC以上，若C未達0.20質量%，則無法得到充分的硬度。又，若C超過0.50質量%，則會形成粗大的碳化物，損及超鏡面最終加工性與耐蝕性。因此，C為0.20～0.50質量%，較佳為0.24～0.45質量%。 "C: 0.20～0.50% by mass" C forms carbides and is an important element that is dissolved in the base of steel to increase its hardness. In order to obtain a super mirror surface, the quenching-tempering hardness of the mold must be 45HRC or more. If C is less than 0.20 mass%, sufficient hardness cannot be obtained. In addition, if C exceeds 0.50% by mass, coarse carbides will be formed, impairing the final workability and corrosion resistance of the super mirror surface. Therefore, C is 0.20 to 0.50 mass%, preferably 0.24 to 0.45 mass%.
「Si：0.10～1.50質量%」 Si基本上是作為鋼液的脫氧材所添加，但是是使鋼材的切削性提升之元素。因此，藉由Si的添加，能夠抑制模具製作成本。若Si未達0.10質量%，則切削性不充分。又，若Si超過1.50質量%，則會增加成分偏析，拋光面產生起伏，同時導熱率會降低。因此，Si係設為0.10～1.50質量%，較佳為設為0.18～1.20質量%。 "Si: 0.10～1.50% by mass" Si is basically added as a deoxidizing material for molten steel, but it is an element that improves the machinability of steel. Therefore, the mold manufacturing cost can be suppressed by adding Si. If the Si content is less than 0.10% by mass, the machinability will be insufficient. In addition, if the Si content exceeds 1.50% by mass, component segregation will increase, the polished surface will have undulations, and the thermal conductivity will decrease. Therefore, the Si content is 0.10 to 1.50% by mass, preferably 0.18 to 1.20% by mass.
「Mn：0.10～0.70質量%」 Mn係使鋼材的淬火性提升之元素。若Mn未達0.10質量%，則無法得到充分的淬火性。又，若Mn超過0.70質量%，則會增加成分偏析，拋光面產生起伏。因此，Mn為0.10～0.70質量%，較佳為0.30～0.60質量%。 "Mn: 0.10～0.70% by mass" Mn is an element that improves the hardenability of steel. If the Mn content is less than 0.10% by mass, sufficient hardenability cannot be obtained. In addition, if Mn exceeds 0.70 mass %, component segregation will increase, causing undulations on the polished surface. Therefore, Mn is 0.10 to 0.70 mass%, preferably 0.30 to 0.60 mass%.
「Cr：10.5～20.0質量%」 Cr係使鋼材的淬火性及耐蝕性提升所需要的元素。若Cr未達10.5質量%，則無法得到充分的淬火性及耐蝕性。又，若Cr超過20.0質量%，則會形成粗大的碳化物，變得無法得到超鏡面性。因此，Cr係添加10.5～20.0質量%。較佳為Cr為12.0～16.0質量%。 "Cr: 10.5～20.0% by mass" Cr is an element required to improve the hardenability and corrosion resistance of steel. If Cr is less than 10.5% by mass, sufficient hardenability and corrosion resistance cannot be obtained. Moreover, if Cr exceeds 20.0 mass %, coarse carbides will be formed, making it impossible to obtain super mirror properties. Therefore, 10.5 to 20.0% by mass of Cr is added. Preferably, Cr is 12.0 to 16.0% by mass.
「Ni：1.00質量%以下」 Ni係使鋼材的淬火性與耐蝕性提升之元素。若該Ni的含量未達0.05質量%，則無法得到該淬火性及耐蝕性的提升效果。因此，Ni較佳為0.05質量%以上。另一方面，若Ni超過1.00質量%，則淬火-回火後的殘留奧氏體(austenite)會增加而變得難以得到超鏡面性。因此，添加1.00質量%以下的Ni。較佳為添加0.05質量%以上的Ni，進一步較佳為添加0.10～0.50質量%的Ni。 "Ni: 1.00% by mass or less" Ni is an element that improves the hardenability and corrosion resistance of steel. If the Ni content is less than 0.05% by mass, the effect of improving the hardenability and corrosion resistance cannot be obtained. Therefore, Ni is preferably 0.05% by mass or more. On the other hand, if Ni exceeds 1.00 mass %, retained austenite (austenite) after quenching and tempering will increase, making it difficult to obtain super mirror properties. Therefore, 1.00% by mass or less of Ni is added. It is preferable to add 0.05 mass % or more of Ni, and it is further more preferable to add 0.10 to 0.50 mass % of Ni.
「Mo：0.05～1.00質量%」 Mo係使耐蝕性及淬火-回火硬度提升之元素。若Mo含量未達0.05質量%，則無法得到耐蝕性及淬火-回火硬度的提升效果。若Mo含量超過1.00質量%，則會形成粗大的碳化物，無法得到超鏡面性，同時製造成本變高。因此，添加0.05～1.00質量%的Mo，較佳為添加0.10～0.60質量%的Mo。 "Mo: 0.05～1.00% by mass" Mo is an element that improves corrosion resistance and quenching-tempering hardness. If the Mo content is less than 0.05% by mass, the effect of improving corrosion resistance and quenching-tempering hardness cannot be obtained. If the Mo content exceeds 1.00% by mass, coarse carbides will be formed, super mirror properties will not be obtained, and the manufacturing cost will increase. Therefore, 0.05 to 1.00% by mass of Mo is added, and preferably 0.10 to 0.60% by mass of Mo is added.
「V：0.01～1.00質量%」 V對於防止鋼材淬火時晶粒的粗大化是有效的。若V未達0.01質量%則無法得到防止晶粒粗大化的效果。另一方面，若V超過1.00質量%，則會形成粗大的碳化物，無法得到超鏡面性，成本亦變高。因此，添加0.01～1.00質量%的V，較佳為添加0.04～0.30%質量%的V。 "V: 0.01～1.00% by mass" V is effective in preventing the coarsening of grains during quenching of steel. If V is less than 0.01 mass %, the effect of preventing grain coarsening cannot be obtained. On the other hand, if V exceeds 1.00 mass %, coarse carbides are formed, super mirror properties cannot be obtained, and the cost becomes high. Therefore, 0.01 to 1.00% by mass of V is added, and preferably 0.04 to 0.30% by mass of V is added.
「Al：0.035質量%以下」 Al基本上是作為鋼液的脫氧材所添加之元素，但是Al會與O鍵結而形成由Al 2O 3構成之非金屬夾雜物，在殘留在鋼液中並凝固的情況下會成為針孔的成因。若Al超過0.035質量%，則會殘留Al 2O 3的團簇，成為針孔的成因，因此變得無法得到超鏡面。因此，Al的容許量係設為0.035質量%。 "Al: 0.035 mass% or less" Al is basically an element added as a deoxidizing material for molten steel. However, Al bonds with O to form non-metallic inclusions composed of Al 2 O 3 and remains in the molten steel. And when solidified, it will cause pinholes. If Al exceeds 0.035 mass %, clusters of Al 2 O 3 remain and cause pinholes, making it impossible to obtain a super mirror surface. Therefore, the allowable amount of Al is set to 0.035% by mass.
「S：0.0020質量%以下」 S係鋼液中所含之雜質，與Mn及Ca鍵結，形成MnS及CaS等硫化物系非金屬夾雜物。此等硫化物與基質及其他非金屬夾雜物相比，具有容易拋光之特徵，因此有引起針孔及橘皮的問題點。若S超過0.0020質量%，則圖2所示之含有CaS之非金屬夾雜物會增加。因此，會產生針孔及橘皮，變得無法得到超鏡面。因此，S係設為0.0020質量%以下。 "S: 0.0020 mass% or less" S is an impurity contained in molten steel and bonds with Mn and Ca to form sulfide non-metallic inclusions such as MnS and CaS. Compared with the matrix and other non-metallic inclusions, these sulfides are easier to polish and therefore cause problems such as pinholes and orange peel. If S exceeds 0.0020 mass%, non-metallic inclusions containing CaS as shown in Figure 2 will increase. Therefore, pinholes and orange peel occur, making it impossible to obtain a super mirror surface. Therefore, the S content is set to 0.0020 mass% or less.
「O：0.0015質量%以下」 O係鋼液中所含之雜質，與Al等鍵結，形成Al 2O 3等氧化物系非金屬夾雜物而為成為針孔的成因之雜質。若該O超過0.0015質量%，則會形成氧化物系非金屬夾雜物的團簇、或非金屬夾雜物的粒徑增大，成為鏡面拋光時產生針孔之原因。由於該針孔的產生，變得無法得到超鏡面。因此，O係設為0.0015質量%以下，較佳為設為0.0009質量%以下。 "O: 0.0015 mass% or less" O-based impurities contained in molten steel bond with Al and the like to form oxide-based non-metallic inclusions such as Al 2 O 3 and other impurities that cause pinholes. If the O content exceeds 0.0015% by mass, clusters of oxide-based non-metallic inclusions may be formed, or the particle size of the non-metallic inclusions may increase, causing pinholes to be generated during mirror polishing. Due to the generation of this pinhole, it becomes impossible to obtain a super mirror surface. Therefore, the O system content is set to 0.0015% by mass or less, preferably 0.0009% by mass or less.
「Ca：0.0020質量%以下」 Ca係與O或S鍵結，形成CaO或CaS，成為針孔的成因。製鋼步驟中，Ca作為精煉劑之熔渣的主要成分存在於鋼液上，因此使鋼液的攪拌條件最佳化，防止熔渣混入鋼液中是重要的。若Ca超過0.0020質量%，則會形成MgO-Al 2O 3-CaO系複合夾雜物或MgO-Al 2O 3-CaS系複合夾雜物，在模具最終拋光時會產生針孔，變得無法得到超鏡面。因此，Ca係設為0.0020質量%以下，較佳為設為0.0010質量%以下。 "Ca: 0.0020 mass% or less" Ca is bonded to O or S to form CaO or CaS, which causes pinholes. In the steelmaking step, Ca is present on the molten steel as the main component of the slag in the refining agent. Therefore, it is important to optimize the stirring conditions of the molten steel and prevent the slag from being mixed into the molten steel. If Ca exceeds 0.0020 mass %, MgO-Al 2 O 3 -CaO-based composite inclusions or MgO-Al 2 O 3 -CaS-based composite inclusions will be formed, resulting in pinholes during final polishing of the mold, making it impossible to obtain Super mirror. Therefore, the Ca content is 0.0020 mass% or less, preferably 0.0010 mass% or less.
「Mg：0.0020質量%以下」 Mg為不可避免的雜質，被限制在0.0020質量%以下。 "Mg: 0.0020 mass% or less" Mg is an unavoidable impurity and is limited to 0.0020 mass% or less.
「Mo+1/2W：0.05～1.00質量%」 W與Mo同樣地，為使耐蝕性及淬火-回火硬度提升之元素。W係其量的1/2的量發揮與Mo相同的效果。也就是說，若W含量以Mo+1/2W計未達0.05質量%，則無法得到耐蝕性及淬火-回火硬度的提升效果。若W含量以Mo+1/2W計超過1.00質量%，則會形成粗大的碳化物，無法得到超鏡面性，同時製造成本變高。因此，因應需要，添加以Mo+1/2W計為0.05～1.00質量%的W，較佳為添加0.10～0.60質量%。 "Mo+1/2W: 0.05～1.00% by mass" W, like Mo, is an element that improves corrosion resistance and quenching-tempering hardness. An amount of 1/2 of the amount of W exhibits the same effect as Mo. In other words, if the W content is less than 0.05% by mass in terms of Mo+1/2W, the effect of improving corrosion resistance and quenching-tempering hardness cannot be obtained. If the W content exceeds 1.00% by mass as Mo+1/2W, coarse carbides will be formed, super mirror properties will not be obtained, and the manufacturing cost will increase. Therefore, if necessary, 0.05 to 1.00 mass % of W calculated as Mo+1/2W is added, and 0.10 to 0.60 mass % is preferably added.
接著，針對非金屬夾雜物的限制理由進行說明。Next, the reasons for the restriction of non-metallic inclusions will be explained.
鋼材剖面中，等效圓直徑8.0μm以上的非金屬夾雜物的面積率為0.00016%以下。In the steel section, the area ratio of non-metallic inclusions with an equivalent circular diameter of 8.0 μm or more is less than 0.00016%.
等效圓直徑為8.0μm以上的非金屬夾雜物，不論其組成，在模具的超鏡面最終加工中皆會使針孔產生而為有害的，因此藉由限制非金屬夾雜物的面積率，來降低針孔的產生機率。因此，等效圓直徑為8.0μm以上的非金屬夾雜物的面積率係設為0.00016%以下。Non-metallic inclusions with an equivalent circular diameter of 8.0 μm or more, regardless of their composition, will cause pinholes in the final processing of the super mirror surface of the mold and are harmful. Therefore, by limiting the area ratio of non-metallic inclusions, Reduce the probability of pinholes. Therefore, the area ratio of non-metallic inclusions with an equivalent circular diameter of 8.0 μm or more is set to 0.00016% or less.
又，以為等效圓直徑為5.0μm以上的非金屬夾雜物，且含有2質量%以上選自由Al、Mg及Ca構成之群組中之任一成分者為對象，在分別設[Ca]、[Mg]、[Al]為[Ca]、[Mg]、[Al]的含量(質量%)，且設為X=[Ca]/([Mg]+[Al])時，X值未達0.3的夾雜物的個數密度未達8.0個/100mm 2，同時X值為0.3以上的夾雜物的個數密度未達3.0個/100mm 2。 In addition, non-metallic inclusions with an equivalent circle diameter of 5.0 μm or more and containing 2 mass % or more of any component selected from the group consisting of Al, Mg, and Ca are considered as objects. Let [Ca], [Mg] and [Al] are the contents (mass %) of [Ca], [Mg] and [Al], and when X=[Ca]/([Mg]+[Al]), the X value does not reach The number density of inclusions with an X value of 0.3 does not reach 8.0/100mm 2 , and the number density of inclusions with an
為了得到超鏡面，需要高潔淨度的模具材料。若如本發明的組成的鋼材般，將S含量低的模具材料予以精煉，則非金屬夾雜物的主體會成為氧化物系夾雜物。該氧化物系夾雜物的主要成分為Ca、Mg、Al，此等元素的來源，Ca係源自使用於精煉之熔渣，Mg係源自耐火物，Al係源自用以減少鋼液的氧量之脫氧材。本案發明人們研究模具材料的超鏡面最終加工性與夾雜物組成的關係之結果，發現為了得到模具材料的優良的超鏡面最終加工性，必須控制氧化物系夾雜物的Ca、Mg、Al的比率。In order to obtain a super mirror surface, high cleanliness mold materials are required. If a mold material with a low S content is refined like the steel material of the composition of the present invention, the main body of the non-metallic inclusions will become oxide-based inclusions. The main components of the oxide inclusions are Ca, Mg, and Al. The sources of these elements are: Ca is derived from the slag used for refining, Mg is derived from the refractory, and Al is derived from the slag used to reduce the molten steel. Oxygen deoxidation material. The inventors of this case studied the relationship between the super-mirror finish workability of mold materials and the composition of inclusions, and found that in order to obtain excellent super-mirror finish workability of mold materials, it is necessary to control the ratios of Ca, Mg, and Al in oxide-based inclusions. .
圖1及圖2為存在於拋光至#14000的超鏡面之模具表面之非金屬夾雜物利用掃描型電子顯微鏡所得之照片。圖1為MgO-Al 2O 3-CaO主體的夾雜物，X值未達0.3。又，圖2為MgO-Al 2O 3-CaS(CaS)系夾雜物，X值為0.3以上。由於Mg及Al會與O鍵結而形成硬質夾雜物，若如圖1般非金屬夾雜物的大小為一定以下則難以形成針孔。鋼液中的Ca、Mg、Al鍵結而形成夾雜物時，確認了對鏡面最終加工性的影響度會依Ca的組成比例而改變。鋼液中的Ca會與微量的S反應，在如圖2般的氧化物系非金屬夾雜物與基底的邊界部分地形成CaS。含有Ca的氧化物CaO之氧化物系夾雜物與硫化物CaS經一體化之複合系夾雜物，與MgO-Al 2O 3系夾雜物相比，容易受到拋光時的化學性影響與物理性影響，會優先地被拋光。因此，成為夾雜物容易脫落之狀態。再者，隨著拋光進行，夾雜物會脫落，產生針孔。因此，夾雜物組成中含有Ca或不含Ca，對於針孔的產生有極為重要的影響。根據本發明人們的研究結果，確認了由等效圓直徑為5.0μm以上的夾雜物組成求得之X值=[Ca]/([Mg]+[Al])未達0.3之夾雜物以個數密度計未達8.0個/100mm 2，同時X值為0.3以上之夾雜物的個數密度未達3.0個/100mm 2之塑膠模具用鋼材係超鏡面最終加工性良好。因此，本發明中，係設為X值未達0.3的夾雜物的個數密度未達8.0個/100mm 2，同時X值為0.3以上的夾雜物的個數密度未達3.0個/100mm 2。 Figures 1 and 2 are photos of non-metallic inclusions present on the surface of a super-mirror mold polished to #14000 using a scanning electron microscope. Figure 1 shows MgO-Al 2 O 3 -CaO-based inclusions, and the X value does not reach 0.3. In addition, Figure 2 shows MgO-Al 2 O 3 -CaS (CaS)-based inclusions, and the X value is 0.3 or more. Since Mg and Al bond with O to form hard inclusions, it is difficult to form pinholes if the size of the non-metallic inclusions is below a certain level as shown in Figure 1. When Ca, Mg, and Al in molten steel bond to form inclusions, it was confirmed that the degree of influence on the final workability of the mirror surface changes depending on the composition ratio of Ca. Ca in the molten steel reacts with trace amounts of S to partially form CaS at the boundary between the oxide-based non-metallic inclusions and the substrate as shown in Figure 2. Composite inclusions in which oxide-based inclusions containing Ca oxides, CaO, and sulfide CaS are integrated, are more susceptible to chemical and physical effects during polishing than MgO-Al 2 O 3- based inclusions. , will be polished preferentially. Therefore, the inclusions become easy to fall off. Furthermore, as polishing proceeds, inclusions will fall off, creating pinholes. Therefore, whether the inclusion composition contains Ca or does not contain Ca has an extremely important impact on the generation of pinholes. According to the research results of the present inventors, it was confirmed that the X value = [Ca]/([Mg] + [Al]) calculated from the composition of inclusions with an equivalent circular diameter of 5.0 μm or more and less than 0.3 was found to be individual. The number density of the inclusions does not reach 8.0/ 100mm2 , and the number density of inclusions with an Therefore, in the present invention, it is assumed that the number density of inclusions with an
這樣規定夾雜物的個數密度，基本上是由實驗結果與鋼材的超鏡面性的關係所求得者。若觀察鋼材的超鏡面最終加工面，MgO-Al 2O 3-CaO(CaS)系夾雜物具有脆的CaS包住MgO-Al 2O 3-CaO的中心核之形狀。此時，若中心核與基底密接，則難以發生夾雜物的脫落，但若成為中心核包埋在CaS中，則變得容易發生夾雜物的脫落。X未達0.3時，中心核與基底較為密接而難以引起夾雜物的脫落，但若X增加至0.3以上，則中心核的CaS所致之包埋會進行，變得容易引起夾雜物的脫落。因此，由實驗結果，確認了以X=0.3為界線，應限制的夾雜物的個數密度會改變。即，確認了在等效圓直徑為8μm以上的非金屬夾雜物的面積率為0.00016%以下的條件下，關於在鏡面最終加工時容易變成針孔之等效圓直徑為5μm以上的非金屬夾雜物，若Ca的組成多且X值為0.3以上則變得容易生成針孔，在個數密度為3個/mm 2以上的情況下超鏡面性差，另一方面，若為Ca的組成比少、Mg及Al主體的非金屬夾雜物，則在個數密度未達8.0個/mm 2的情況下可得到超鏡面性。因此，容許X值未達0.3的夾雜物的個數密度至未達8.0個/100mm 2，容許X值為0.3以上的夾雜物的個數密度至3.0個/100mm 2。 [實施例] The number density of inclusions specified in this way is basically obtained from the relationship between experimental results and the supermirror properties of steel. If the super-mirror final processed surface of the steel is observed, the MgO-Al 2 O 3 -CaO (CaS) inclusions have a shape in which brittle CaS surrounds the central core of MgO-Al 2 O 3 -CaO. At this time, if the center core is in close contact with the substrate, it is difficult for the inclusions to fall off. However, if the center core is embedded in CaS, the inclusions will easily fall off. When X is less than 0.3, the central core is in close contact with the substrate and it is difficult to cause inclusions to fall off. However, if Therefore, from the experimental results, it was confirmed that the number density of inclusions that should be restricted changes when X=0.3 is used as the boundary. That is, it was confirmed that under the condition that the area ratio of non-metallic inclusions with an equivalent circular diameter of 8 μm or more is 0.00016% or less, non-metallic inclusions with an equivalent circular diameter of 5 μm or more are likely to become pinholes during final processing of the mirror surface. If the composition of Ca is large and the , Mg and Al-based non-metallic inclusions, super mirror properties can be obtained when the number density does not reach 8.0/ mm2 . Therefore, the number density of inclusions with an X value of less than 0.3 is allowed to be less than 8.0 inclusions/100mm 2 , and the number density of inclusions with an X value of 0.3 or more is allowed to be up to 3.0 inclusions/100mm 2 . [Example]
接著，針對劃入本發明的範圍之實施例，與在本發明的範圍外之比較例一起進行說明。Next, examples falling within the scope of the present invention will be described together with comparative examples that fall outside the scope of the invention.
在使用量產電爐與爐外精煉裝置之一次精煉時，比平常更加強脫氧處理、脫硫處理、及脫氣處理，熔製高潔淨度鋼，製造電極。以該電極為基礎，利用VAR(真空電弧重熔法)或ESR(電渣重熔法)進行二次精煉，將所得之鋼塊熱鍛成150～250mm厚、200～400mm寬的尺寸，之後進行退火處理。下述表1中，針對本發明的實施例1～14及在本發明的範圍外之比較例16～23顯示製造之鋼材的組成。此外，參考例15係Al成分在本發明的範圍外者，但如表2所示，關於非金屬夾雜物之條件係滿足本發明的範圍。其中，表1中，數值為質量%。本發明係發現以下事情所完成者：為了創造出超鏡面，即使為極力減少夾雜物之高潔淨度鋼，取決於殘留之氧化物系夾雜物的組成，即取決於夾雜物所含之Ca的比例，超鏡面性仍會受到影響。When using one of the mass-produced electric furnaces and refining equipment outside the furnace for primary refining, deoxidation, desulfurization, and degassing are performed more intensively than usual to melt high-purity steel and manufacture electrodes. Based on this electrode, VAR (vacuum arc remelting) or ESR (electroslag remelting) is used for secondary refining, and the resulting steel block is hot forged into a size of 150 to 250 mm thick and 200 to 400 mm wide. Perform annealing treatment. Table 1 below shows the compositions of steel materials produced in Examples 1 to 14 of the present invention and Comparative Examples 16 to 23, which are outside the scope of the present invention. In addition, Reference Example 15 has an Al component outside the scope of the present invention, but as shown in Table 2, the conditions regarding non-metallic inclusions satisfy the scope of the present invention. Among them, in Table 1, the numerical values are mass %. The present invention was accomplished by discovering that in order to create a supermirror surface, even in high-clean steel with minimal inclusions, the composition of the remaining oxide-based inclusions, that is, the Ca contained in the inclusions, depends on the composition. Proportions, hyperspecularity will still be affected.
Ca係以在一次精煉時存在於熔渣中之Ca為主要的來源，因此本發明中，以熔渣不會捲入精煉時的鋼液的方式，改善操作條件。高潔淨度鋼的精煉除了脫氣之外，還會促進鋼液與熔渣之間的反應以去除雜質。為了促進反應，需要藉由攪拌鋼液以增加鋼液上的熔渣與鋼液的直接接觸，但過度的鋼液攪拌會將熔渣捲入鋼液中，無法完全浮起分離的熔渣會殘留在鋼液中成為夾雜物。因此，無法得到高潔淨度的鋼液，含熔渣的成分會殘留在鋼液中，鋼材中的夾雜物會增加。The main source of Ca is Ca present in the molten slag during primary refining. Therefore, in the present invention, the operating conditions are improved so that molten steel is not involved in the molten steel during refining. In addition to degassing, the refining of high-cleanliness steel also promotes the reaction between the molten steel and the slag to remove impurities. In order to promote the reaction, it is necessary to stir the molten steel to increase the direct contact between the slag on the molten steel and the molten steel. However, excessive stirring of the molten steel will drag the slag into the molten steel, and the slag that cannot be completely floated and separated will be Remains in the molten steel and becomes inclusions. Therefore, high-purity molten steel cannot be obtained, components containing slag will remain in the molten steel, and inclusions in the steel will increase.
另一方面，鋼液攪拌的方法有從鋼包底部導入惰性氣體之氣體攪拌與電磁攪拌之方法，依鋼包形狀與鋼液量，決定氣體攪拌力與電磁攪拌力的比率作為操作條件。利用氣體之攪拌力，由於藉由脫氣而真空度會提高，即使為相同氣體量仍會變化而增大，因此需要控制。本發明人們藉由分析殘留在製品中之夾雜物的量與組成，探討即使在二次精煉中仍無法去除之一次精煉時的熔渣捲入狀況，重新審視以往的操作條件，發現以電磁攪拌作為主攪拌力之最佳條件範圍。將攪拌力控制在充分地促進反應且不會變成過度的範圍，防止一次精煉時的熔渣捲入，使夾雜物量減少以達成高潔淨度，且進行X值的控制。熔渣成分及其黏度會對夾雜物組成及熔渣的捲入容易度造成影響，因此藉由一起進行熔渣成分的控制，確保X值的控制。藉此，與以往的模具用鋼相比，能夠作成適於鏡面最終加工性之模具鋼。On the other hand, methods for stirring molten steel include gas stirring and electromagnetic stirring, which introduce inert gas from the bottom of the ladle. Depending on the shape of the ladle and the amount of molten steel, the ratio of gas stirring force and electromagnetic stirring force is determined as the operating condition. Utilizing the stirring force of gas, the degree of vacuum will increase through degassing, and even if the amount of gas is the same, it will still change and increase, so control is required. By analyzing the amount and composition of inclusions remaining in the product, the inventors explored the situation of slag inclusion during primary refining that could not be removed even in secondary refining, re-examined the previous operating conditions, and found that electromagnetic stirring As the optimal condition range for the main stirring force. The stirring force is controlled within a range that sufficiently promotes the reaction without becoming excessive, prevents slag from being involved during primary refining, reduces the amount of inclusions to achieve high cleanliness, and controls the X value. The slag composition and its viscosity affect the composition of inclusions and the ease of slag entanglement, so by controlling the slag composition at the same time, control of the X value is ensured. This makes it possible to produce a mold steel suitable for mirror finish workability compared to conventional mold steels.
[表1] [Table 1]
從該鋼材，採取鏡面最終加工性評價試驗片與夾雜物評價試驗片。鏡面最終加工性評價試驗片係相對於鍛造方向垂直地採取縱50mm、橫50mm作為試驗面(厚度15mm)，實施粗加工後，在1000～1100℃的溫度將各試驗片予以淬火，在500～600℃的溫度進行高溫回火，以硬度成為48～54HRC的方式進行調質，實施最終加工。利用砥石#600將該50×50mm的試驗面予以拋光後，利用砂紙拋光至#400～#1500，使用6～1μm的鑽石磨料，拋光至#14000的超鏡面，利用目視進行鏡面觀察。該鏡面觀察係實際上製造#14000的超鏡面塑膠模具之最終處理器來判定。From this steel material, test pieces for mirror final workability evaluation and test pieces for inclusion evaluation were taken. The mirror surface final workability evaluation test piece is a test surface with a length of 50 mm and a width of 50 mm perpendicular to the forging direction (thickness: 15 mm). After rough machining, each test piece is quenched at a temperature of 1000 to 1100°C. High-temperature tempering is carried out at a temperature of 600°C, quenching and tempering is performed so that the hardness becomes 48 to 54HRC, and final processing is performed. Use grindstone #600 to polish the 50×50mm test surface, use sandpaper to polish to #400~#1500, use 6~1 μm diamond abrasives, polish to #14000 super mirror surface, and observe the mirror surface visually. The mirror observation is determined by the final processor of the actual manufacturing #14000 super mirror plastic mold.
夾雜物評價試驗片係在與鏡面最終加工性評價試驗片相同的位置將相同的方向作為試驗面，採取縱20mm×橫20mm(厚度15mm)的大小者，實施粗加工後，在1000～1100℃的溫度進行淬火處理。之後，利用砂紙將測定面階段性地從#80拋光至#1500，使用6μm～1μm的鑽石磨料，拋光至#14000的超鏡面。存在於試驗片之非金屬夾雜物的調查，係對試驗片進行SEM(掃描型電子顯微鏡)-EDX(能量色散X射線分析)與粒子解析來進行。分析區域係設為在夾雜物的面積包含70%左右之區域。The inclusion evaluation test piece is taken at the same position as the mirror finish workability evaluation test piece, with the same direction as the test surface, and is 20 mm in length × 20 mm in width (thickness: 15 mm). After rough processing, it is processed at 1000 to 1100°C. temperature for quenching treatment. Thereafter, the measurement surface was polished step by step from #80 to #1500 using sandpaper, and polished to a super mirror surface of #14000 using 6 μm to 1 μm diamond abrasives. The investigation of non-metallic inclusions present in the test piece is carried out by performing SEM (Scanning Electron Microscope)-EDX (Energy Dispersive X-ray Analysis) and particle analysis on the test piece. The analysis area is set to an area containing approximately 70% of the inclusion area.
非金屬夾雜物的評價係利用以下的程序來實施。首先，在100倍的觀察視野，求得2次電子影像。此時，藉由對比以基底成為灰色、非金屬夾雜物成為黑色的方式進行拍攝。接著，對於視野內的黑色部分為等效圓直徑3μm以上的粒子，如圖3所示般，利用EDX將剖面積約70%的區域予以組成分析。近似於圖3的圓形之黑色部分為非金屬夾雜物的剖面，散布在該黑色部分內之點，顯示利用EDX(能量色散X射線分析)所分析之部分。從所得之粒子，利用組成過濾器將非金屬夾雜物以外的灰塵及拋光損傷等干擾去除。由去除干擾所得之粒子得到全部非金屬夾雜物的面積率。又，對於Al、Mg、Ca之任一者為2%以上的非金屬夾雜物，算出X值，求得X值＜0.3的個數密度(=檢測個數/分析面積)與X值≧0.3的個數密度。The evaluation of non-metallic inclusions is carried out using the following procedures. First, a secondary electronic image is obtained at an observation field of 100 times. At this time, the image is photographed so that the base becomes gray and the non-metallic inclusions become black by contrast. Next, for particles whose black portion in the field of view has an equivalent circle diameter of 3 μm or more, as shown in Figure 3, a region with a cross-sectional area of about 70% is analyzed for composition using EDX. The black portion approximately circular in Figure 3 is the cross-section of the non-metallic inclusion, and the points scattered within the black portion show the portion analyzed using EDX (Energy Dispersive X-ray Analysis). From the obtained particles, a composition filter is used to remove interference such as dust and polishing damage other than non-metallic inclusions. The area ratio of all non-metallic inclusions is obtained from the particles obtained by removing interference. Also, for non-metallic inclusions containing more than 2% of any of Al, Mg, and Ca, calculate the number density.
其結果，非金屬夾雜物的測定結果係如下述表2所示。表2所示之鏡面最終加工性，係將經最終加工之模具表面，在充分明亮的照明下傾斜各種角度，以目視確認面的反射情況，因有有害的針孔導致鏡面性降低的情況評為「×」，沒有鏡面性降低的情況評為「○」。模具的工作面的鏡面性評價，係以使用模具所加工之製品的表面的美觀來進行最終地判定。實際的製品表面的評價，係製品的合格與否。然而，發生製品不良之評價會對實際生產的效率與成本造成不良影響，因此使用模具觀察的評價並不實際。因此，將製品加工所使用之模具表面予以拋光加工之處理器，係由經驗上對模具工作面整體進行官能評價來判斷。具體而言，以模具工作面整體為對象，對最終加工鏡面進行官能評價，使鏡面性降低之針孔存在有單數或複數處時，處理器會將其找出，將該模具予以再拋光以形成新生成面，進行再拋光加工直到工作面整體得到超鏡面。又，鏡面最終加工性差的材料的情況下，亦有判斷為不可使用的情況。該針孔的大小及出現頻率，係在模具工作面整體廣泛地進行評價，因此部分的表面粗糙度及反射率等數據是不充分的。因此，依利用處理器的官能評價所得之判斷，將因夾雜物而需要再拋光加工者評為×，設不進行再拋光而可得到超鏡面者評為○(合格)。As a result, the measurement results of non-metallic inclusions are shown in Table 2 below. The final processability of the mirror surface shown in Table 2 is based on the evaluation of the final processed mold surface, which is tilted at various angles under sufficient bright lighting to visually confirm the reflection of the surface. The mirror properties are reduced due to harmful pinholes. It is rated as "×", and the case where there is no deterioration in specularity is rated as "○". The mirror finish evaluation of the working surface of the mold is ultimately judged based on the appearance of the surface of the product processed using the mold. The actual evaluation of the product surface determines whether the product is qualified or not. However, the evaluation of defective products will have a negative impact on actual production efficiency and cost, so evaluation using mold observation is not practical. Therefore, the processor that polishes the surface of the mold used in product processing is judged by empirically conducting a sensory evaluation of the entire working surface of the mold. Specifically, the entire working surface of the mold is used as an object to perform a sensory evaluation on the final processed mirror surface. If there are odd or plural pinholes that reduce the mirror properties, the processor will find them and re-polishing the mold. A new generated surface is formed and repolished until the entire working surface obtains a super mirror surface. In addition, in the case of materials with poor final processability of the mirror surface, it may be judged as unusable. The size and frequency of occurrence of these pinholes are extensively evaluated on the entire working surface of the mold, so some data such as surface roughness and reflectivity are insufficient. Therefore, based on the judgment obtained by the sensory evaluation using a processor, those that require re-polishing due to inclusions will be rated as ×, and those that can obtain a super mirror surface without re-polishing will be rated as ○ (passed).
[表2] [Table 2]
如該表2所示，等效圓直徑8.0μm以上的非金屬夾雜物的面積率為0.00016%以下、X值未達0.3的夾雜物的個數密度未達8.0個/100mm 2、X值為0.3以上的夾雜物的個數密度未達3.0個/100mm 2之實施例的情況下，可得到鏡面最終加工性優良的模具用鋼。另一方面，上述要素之任1個在本發明的範圍外之比較例的情況下，鏡面最終加工性差。 [產業上的可利用性] As shown in Table 2, the area ratio of non-metallic inclusions with an equivalent circular diameter of 8.0 μm or more is 0.00016% or less, the number density of inclusions with an X value less than 0.3 is less than 8.0/100mm 2 , and the X value is In the case of the example in which the number density of inclusions of 0.3 or more is less than 3.0/ 100mm2 , mold steel with excellent mirror finish processability can be obtained. On the other hand, in the case of a comparative example in which any one of the above elements is outside the scope of the present invention, the final mirror surface workability is poor. [Industrial availability]
根據本發明，模具表面的超鏡面最終加工變得容易，因此有益於得到需要利用這樣的模具所進行之成形加工的塑膠製品的表面的超鏡面。According to the present invention, the final processing of the super-mirror surface of the mold surface becomes easy, and therefore it is beneficial to obtain the super-mirror surface of the surface of the plastic product that needs to be formed using such a mold.
[圖1]圖1為MgO-Al 2O 3系夾雜物的掃描型電子顯微鏡照片。 [圖2]圖2為MgO-Al 2O 3-CaS系夾雜物的掃描型電子顯微鏡照片。 [圖3]圖3為顯示被檢測之粒子的分析方法之圖。 [Fig. 1] Fig. 1 is a scanning electron microscope photograph of MgO-Al 2 O 3- based inclusions. [Figure 2] Figure 2 is a scanning electron microscope photograph of MgO-Al 2 O 3 -CaS inclusions. [Fig. 3] Fig. 3 is a diagram showing an analysis method of detected particles.
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| TW200643190A (en) * | 2005-06-02 | 2006-12-16 | Daido Steel Co Ltd | Steel for a plastic molding die |
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| JP2017171983A (en) * | 2016-03-23 | 2017-09-28 | 株式会社神戸製鋼所 | Method for reducing coarse inclusion by lf treatment |
| CN113355598A (en) * | 2021-05-24 | 2021-09-07 | 如皋市宏茂重型锻压有限公司 | High-grade mirror surface gum die steel and manufacturing process thereof |
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| CN106460108A (en) * | 2014-03-06 | 2017-02-22 | 日本高周波钢业株式会社 | Steel for mold for plastic with high specularity |
| JP2017171983A (en) * | 2016-03-23 | 2017-09-28 | 株式会社神戸製鋼所 | Method for reducing coarse inclusion by lf treatment |
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